1. Field of the Invention
The present invention relates generally to installing electrical devices, such as thermostats, at points of operation and, more particularly, to an apparatus for aiding an installer in properly wiring an electrical device where the electrical device is capable of multiple wiring configurations.
2. Description of Related Art
Electrical service points, such as residential, commercial, industrial, and agricultural properties, include a variety of different systems that use utility-supplied and/or locally-generated alternating current electrical power. Such systems include, for example, heating, ventilation, and air conditioning (HVAC) systems, sprinkler systems, lighting systems, aquatic systems (e.g., pools and fountains), industrial systems, and surveillance systems, just to name a few. Many of these systems include electrical control devices, which control when the systems turn on and off. For example, an HVAC system typically includes one or more thermostats that control when the system's air conditioning compressor, fan motor, heat pump, furnace, or heating element, as applicable, turns on and off based on temperature set points stored in each thermostat (an HVAC system may include multiple thermostats where the system has multiple heating/cooling zones or where the system includes separate thermostats for heating and cooling). Additionally, a lighting system typically includes one or more timers, optical sensors, and/or motion sensors that control when the illumination elements (e.g., lamps, lights, or bulbs) turn on and off. Further, a sprinkler system typically includes one or more timers and/or rain sensors that control when the sprinkler pump motor turns on and off.
Nowadays, many electrical devices used to control service point systems are flexibly designed to work with a variety of different systems. For example, some thermostats are designed to be used with just about any HVAC system, whether conventional furnace or heat pump, 4-wire or 5-wire, single stage heat/cool or multi-stage heat/cool, or electric or natural gas. One such thermostat is the model CT30 wireless thermostat, which is commercially available from Radio Thermostats of America of San Francisco, Calif. An exemplary illustration of a wiring terminal panel for such a wireless thermostat 100 is shown in FIG. 1.
As illustrated, the thermostat 100 includes a housing 101, several exposed wiring terminals 103-113, two setting switches 115, 117, and a reset switch 119. The settings of the setting switches 115, 117 and the installation of wires into the wiring terminals 103-113 (i.e., the wiring configuration) depends on the particular type of HVAC system to be controlled by the thermostat 100. For example, when the HVAC system is a conventional, 4-wire, electric system, the normal/HP setting switch 115 should be set to “NORM”, the gas/electric setting switch 117 should be set to “ELEC”, the blue common wire from the HVAC system should be installed into the “C” wiring terminal 103, the white “heat” control wire for the HVAC system should be installed in the “W” wiring terminal 106, the yellow “cool” control wire for the HVAC system should be installed in the “Y” wiring terminal 108, the red +24 Volt wire from the HVAC system should be installed in the “RC” wiring terminal 111, and the green “fan” wire for the HVAC system should be installed in the “G” wiring terminal 112. Alternatively, as another example, when the HVAC system is a 5-wire heat pump system with auxiliary heat, the normal/HP setting switch 115 should be set to “HP”, the gas/electric setting switch 117 should be set to “ELEC” or “GAS”, as applicable, the blue common wire from the HVAC system should be installed into the “C” wiring terminal 103, the orange “reversing valve” control wire for the HVAC system should be installed in the “B” wiring terminal 104, the black “auxiliary heat” wire should be installed in the “W2” wiring terminal 107, the yellow “cool” control wire for the HVAC system should be installed in the “Y” wiring terminal 108, the red +24 Volt wire from the HVAC system should be installed in the “RC” wiring terminal 111, and the green “fan” wire for the HVAC system should be installed in the “G” wiring terminal 112. Thus, while some of the thermostat wiring for the two exemplary HVAC systems is the same, some is also different, resulting in two distinct wiring configurations.
Due to the various possible wiring configurations for some electrical devices, miswiring mistakes occasionally occur during installation of such devices at their respective points of operation. Such miswiring can result in safety issues, defective operation or failure of the system controlled by the miswired electrical device, and/or damage to the electrical device. Therefore, a need exists for a tool which can be used by installers, service technicians, and/or end users to mitigate the likelihood of miswiring mistakes during installation and/or servicing of electrical devices, where such electrical devices are capable of being wired in any one of multiple wiring configurations.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated alone or relative to other elements to help improve the understanding of the various embodiments of the present invention.